#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include "zmalloc.h"
#include "concurrent/concurrent.h"

#ifdef HAVE_MALLOC_SIZE
#define PREFIX_SIZE (0)
#else
#if defined(__sun) || defined(__sparc) || defined(__sparc__)
#define PREFIX_SIZE (sizeof(long long))
#else
#define PREFIX_SIZE (sizeof(size_t))
#endif
#endif

/* Explicitly override malloc/free etc when using tcmalloc. */
#if defined(USE_TCMALLOC)
#define malloc(size) tc_malloc(size)
#define calloc(count,size) tc_calloc(count,size)
#define realloc(ptr,size) tc_realloc(ptr,size)
#define free(ptr) tc_free(ptr)
#elif defined(USE_JEMALLOC)
#define malloc(size) je_malloc(size)
#define calloc(count,size) je_calloc(count,size)
#define realloc(ptr,size) je_realloc(ptr,size)
#define free(ptr) je_free(ptr)
#endif

#ifdef ZMALLOC_SAFE
#define NUM_INC(x,y)  atomic_add_get(&(x),(y))
#define NUM_GET(x) atomic_get(&(x))
#else
#define NUM_INC(x,y) (x)+=(y)
#define NUM_GET(x) (x)
#endif

static size_t used_memory = 0;

#define update_zmalloc_stat_alloc(__n,__size) do { \
    size_t _n = (__n); \
    if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
    NUM_INC(used_memory,_n);\
} while(0)

#define update_zmalloc_stat_free(__n) do { \
    size_t _n = (__n); \
    if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); \
    NUM_INC(used_memory,-_n);\
} while(0)

static void zmalloc_oom(size_t size) {
    fprintf(stderr, "zmalloc: Out of memory trying to allocate %zu bytes\n",
            size);
    fflush(stderr);
    abort();
}

void *zmalloc(size_t size) {
    void *ptr = malloc(size + PREFIX_SIZE);

    if (!ptr)
        zmalloc_oom(size);
#ifdef HAVE_MALLOC_SIZE
    update_zmalloc_stat_alloc(zmalloc_size(ptr),size);
    return ptr;
#else
    *((size_t*) ptr) = size;
    update_zmalloc_stat_alloc(size+PREFIX_SIZE, size);
    return (char*) ptr + PREFIX_SIZE;
#endif
}

void *zcalloc(size_t size) {
    void *ptr = calloc(1, size + PREFIX_SIZE);

    if (!ptr)
        zmalloc_oom(size);
#ifdef HAVE_MALLOC_SIZE
    update_zmalloc_stat_alloc(zmalloc_size(ptr),size);
    return ptr;
#else
    *((size_t*) ptr) = size;
    update_zmalloc_stat_alloc(size+PREFIX_SIZE, size);
    return (char*) ptr + PREFIX_SIZE;
#endif
}

void *zrealloc(void *ptr, size_t size) {
#ifndef HAVE_MALLOC_SIZE
    void *realptr;
#endif
    size_t oldsize;
    void *newptr;

    if (ptr == NULL)
        return zmalloc(size);
#ifdef HAVE_MALLOC_SIZE
    oldsize = zmalloc_size(ptr);
    newptr = realloc(ptr,size);
    if (!newptr) zmalloc_oom(size);

    update_zmalloc_stat_free(oldsize);
    update_zmalloc_stat_alloc(zmalloc_size(newptr),size);
    return newptr;
#else
    realptr = (char*) ptr - PREFIX_SIZE;
    oldsize = *((size_t*) realptr);
    newptr = realloc(realptr, size + PREFIX_SIZE);
    if (!newptr)
        zmalloc_oom(size);

    *((size_t*) newptr) = size;
    update_zmalloc_stat_free(oldsize);
    update_zmalloc_stat_alloc(size, size);
    return (char*) newptr + PREFIX_SIZE;
#endif
}

/* Provide zmalloc_size() for systems where this function is not provided by
 * malloc itself, given that in that case we store an header with this
 * information as the first bytes of every allocation. */
#ifndef HAVE_MALLOC_SIZE
size_t zmalloc_size(void *ptr) {
    void *realptr = (char*) ptr - PREFIX_SIZE;
    size_t size = *((size_t*) realptr);
    /* Assume at least that all the allocations are padded at sizeof(long) by
     * the underlying allocator. */
    if (size & (sizeof(long) - 1))
        size += sizeof(long) - (size & (sizeof(long) - 1));
    return size + PREFIX_SIZE;
}
#endif
void zfree(void *ptr) {
#ifndef HAVE_MALLOC_SIZE
    void *realptr;
    size_t oldsize;
#endif

    if (ptr == NULL)
        return;
#ifdef HAVE_MALLOC_SIZE
    update_zmalloc_stat_free(zmalloc_size(ptr));
    free(ptr);
#else
    realptr = (char*) ptr - PREFIX_SIZE;
    oldsize = *((size_t*) realptr);
    update_zmalloc_stat_free(oldsize+PREFIX_SIZE);
    free(realptr);
#endif
}

size_t zmalloc_used_memory(void) {
    return NUM_GET(used_memory);
}

/* Get the RSS information in an OS-specific way.
 *
 * WARNING: the function zmalloc_get_rss() is not designed to be fast
 * and may not be called in the busy loops where Redis tries to release
 * memory expiring or swapping out objects.
 *
 * For this kind of "fast RSS reporting" usages use instead the
 * function RedisEstimateRSS() that is a much faster (and less precise)
 * version of the funciton. */

#if defined(HAVE_PROCFS)
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

size_t zmalloc_get_rss(void) {
    int page = sysconf(_SC_PAGESIZE);
    size_t rss;
    char buf[4096];
    char filename[256];
    int fd, count;
    char *p, *x;

    snprintf(filename,256,"/proc/%d/stat",getpid());
    if ((fd = open(filename,O_RDONLY)) == -1) return 0;
    if (read(fd,buf,4096) <= 0) {
        close(fd);
        return 0;
    }
    close(fd);

    p = buf;
    count = 23; /* RSS is the 24th field in /proc/<pid>/stat */
    while(p && count--) {
        p = strchr(p,' ');
        if (p) p++;
    }
    if (!p) return 0;
    x = strchr(p,' ');
    if (!x) return 0;
    *x = '\0';

    rss = strtoll(p,NULL,10);
    rss *= page;
    return rss;
}
#elif defined(HAVE_TASKINFO)
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <mach/task.h>
#include <mach/mach_init.h>

size_t zmalloc_get_rss(void) {
    task_t task = MACH_PORT_NULL;
    struct task_basic_info t_info;
    mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;

    if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
    return 0;
    task_info(task, TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count);

    return t_info.resident_size;
}
#else
size_t zmalloc_get_rss(void) {
    /* If we can't get the RSS in an OS-specific way for this system just
     * return the memory usage we estimated in zmalloc()..
     *
     * Fragmentation will appear to be always 1 (no fragmentation)
     * of course... */
    return zmalloc_used_memory();
}
#endif

/* Fragmentation = RSS / allocated-bytes */
float zmalloc_get_fragmentation_ratio(void) {
    return (float) zmalloc_get_rss() / zmalloc_used_memory();
}
